The bottom of the wetsuit fabric marine sock is perfect for full foot fins and has a non-slip finish. When diving in Okinawa or overseas or boating dives, your feet are cold when diving in full-foot type fins. Fins feel a little loose... Do you feel frustrated? When diving, feel like socks. Eliminates cold feet Also great for fins size adjustment. It also has a thermal effect. Sizes: S (8.7 - 9.1 inches (22 - 23 cm), M (9.4 - 9.8 inches (24 - 25 cm), L (10.2 - 10.6 inches (26 - 27 cm), XL (11.0 inches (28 cm); Material: Front and back jerse